| Message ID | 20200925093109.388661-1-nobuhiro1.iwamatsu@toshiba.co.jp |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [for,4.14,4.19] serial: 8250: Avoid error message on reprobe | expand |
On Fri, Sep 25, 2020 at 06:31:09PM +0900, Nobuhiro Iwamatsu wrote: > From: Lukas Wunner <lukas@wunner.de> > > commit e0a851fe6b9b619527bd928aa93caaddd003f70c upstream. > > If the call to uart_add_one_port() in serial8250_register_8250_port() > fails, a half-initialized entry in the serial_8250ports[] array is left > behind. > > A subsequent reprobe of the same serial port causes that entry to be > reused. Because uart->port.dev is set, uart_remove_one_port() is called > for the half-initialized entry and bails out with an error message: > > bcm2835-aux-uart 3f215040.serial: Removing wrong port: (null) != (ptrval) > > The same happens on failure of mctrl_gpio_init() since commit > 4a96895f74c9 ("tty/serial/8250: use mctrl_gpio helpers"). > > Fix by zeroing the uart->port.dev pointer in the probe error path. > > The bug was introduced in v2.6.10 by historical commit befff6f5bf5f > ("[SERIAL] Add new port registration/unregistration functions."): > https://git.kernel.org/tglx/history/c/befff6f5bf5f > > The commit added an unconditional call to uart_remove_one_port() in > serial8250_register_port(). In v3.7, commit 835d844d1a28 ("8250_pnp: > do pnp probe before legacy probe") made that call conditional on > uart->port.dev which allows me to fix the issue by zeroing that pointer > in the error path. Thus, the present commit will fix the problem as far > back as v3.7 whereas still older versions need to also cherry-pick > 835d844d1a28. > > Fixes: 835d844d1a28 ("8250_pnp: do pnp probe before legacy probe") > Signed-off-by: Lukas Wunner <lukas@wunner.de> > Cc: stable@vger.kernel.org # v2.6.10 > Cc: stable@vger.kernel.org # v2.6.10: 835d844d1a28: 8250_pnp: do pnp probe before legacy > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > Link: https://lore.kernel.org/r/b4a072013ee1a1d13ee06b4325afb19bda57ca1b.1589285873.git.lukas@wunner.de > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > [iwamatsu: Backported to 4.14, 4.19: adjust context] > Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp> Thanks, now queue dup. greg k-h
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index d6b790510c94..8d46bd612888 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -1065,8 +1065,10 @@ int serial8250_register_8250_port(struct uart_8250_port *up) serial8250_apply_quirks(uart); ret = uart_add_one_port(&serial8250_reg, &uart->port); - if (ret == 0) - ret = uart->port.line; + if (ret) + goto err; + + ret = uart->port.line; } else { dev_info(uart->port.dev, "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n", @@ -1091,6 +1093,11 @@ int serial8250_register_8250_port(struct uart_8250_port *up) mutex_unlock(&serial_mutex); return ret; + +err: + uart->port.dev = NULL; + mutex_unlock(&serial_mutex); + return ret; } EXPORT_SYMBOL(serial8250_register_8250_port);